Background:Anteromedial rotatory instability (AMRI) of the knee is a complex and severe condition caused by injury to the anterior cruciate ligament and/or the medial collateral ligament. Clinical studies dealing with AMRI are rare, and objective measurements are nonexistent.Purpose/Hypothesis:The objectives of this study were, first, to quantify anteromedial rotatory knee laxity in healthy individuals using a noninvasive image analysis software and, second, to assess intra- and interrater reliability and equivalence in measuring anteromedial knee translation (AMT). It was hypothesized that AMT could be reliably quantified using a noninvasive image analysis software.Study design:Cohort study; Level of evidence, 3.Methods:This prospective proof-of-concept study included healthy individuals aged 16 to 40 years with no history of knee injury or surgery. Three adhesive surface markers were placed on predefined landmarks on the medial side of the knee. Three independent investigators examined anteromedial rotatory knee laxity with an anterior drawer test in different tibial rotations (neutral tibial rotation, 15° of external tibial rotation, and 15° of internal tibial rotation). The entire examination of each knee was recorded, and AMT including the side-to-side difference (SSD) was assessed using a freely available and validated image analysis software (PIVOT iPad application). Group comparisons were performed using a 1-way analysis of variance with Bonferroni-adjusted post hoc analysis. Intraclass correlation coefficients (ICCs) were calculated to assess inter- and intrarater reliability of AMT measurements. Equivalence of measurements was evaluated using the 2 one-sided t-test procedure.Results:Anteromedial rotatory knee laxity was assessed in 30 knees of 15 participants (53% male) with a mean age of 26.2 ± 3.5 years. In all 3 raters, the highest AMT was observed in neutral tibial rotation (range of means, 2.2-3.0 mm), followed by external tibial rotation (range of means, 2.0-2.4 mm) and internal tibial rotation (range of means, 1.8-2.2 mm; P < .05). Intrarater reliability of AMT (ICC, 0.88-0.96) and SSD (ICC, 0.61-0.96) measurements was good to excellent and moderate to excellent, respectively. However, interrater reliability was poor to moderate for AMT (ICC, 0.44-0.73) and SSD (ICC, 0.12-0.69) measurements. Statistically significant equivalence of AMT and SSD measurements was observed between and within raters for almost all testing conditions.Conclusion:Anteromedial rotatory knee laxity could be quantified using a noninvasive image analysis software, with the highest AMT observed during neutral tibial rotation in uninjured individuals. Reliability and equivalence of measurements were good to excellent within raters and moderate between raters.

中文翻译：

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前内侧旋转膝关节松弛的无创且可靠的量化：针对健康个体的初步研究

背景：膝关节前内侧旋转不稳定（AMRI）是由前交叉韧带和/或内侧副韧带损伤引起的复杂而严重的疾病。涉及 AMRI 的临床研究很少，也不存在客观测量。 目的/假设：本研究的目的首先是使用无创图像分析软件量化健康个体的前内侧旋转膝关节松弛度，其次是评估内部旋转性膝关节松弛度。以及测量膝关节前内侧平移 (AMT) 时的受试者间可靠性和等效性。假设使用非侵入性图像分析软件可以可靠地量化 AMT。 研究设计：队列研究；证据级别，3。方法：这项前瞻性概念验证研究纳入了 16 至 40 岁、没有膝关节损伤或手术史的健康个体。三个粘性表面标记被放置在膝盖内侧的预定标志上。三名独立研究者通过不同胫骨旋转（胫骨中立旋转、胫骨外旋 15° 和胫骨内旋 15°）下的前抽屉试验检查了前内侧旋转膝关节松弛度。记录每个膝盖的整个检查，并使用免费提供且经过验证的图像分析软件（PIVOT iPad 应用程序）评估 AMT，包括左右差异 (SSD)。使用单向方差分析和 Bonferroni 调整事后分析进行组比较。计算组内相关系数 (ICC) 以评估 AMT 测量值的评估者间和评估者内可靠性。使用 2 个单侧 t 检验程序评估测量结果的等效性。 结果：对平均年龄为 26.2 ± 3.5 岁的 15 名参与者（53% 男性）的 30 个膝盖进行前内侧旋转膝关节松弛度评估。在所有 3 名评估者中，观察到最高的 AMT 是胫骨中立旋转（平均值范围，2.2-3.0 mm），其次是胫骨外旋转（平均值范围，2.0-2.4 mm）和胫骨内旋转（平均值范围，1.8） -2.2 毫米；P < .05)。 AMT（ICC，0.88-0.96）和 SSD（ICC，0.61-0.96）测量的评估者内可靠性分别为良好至优秀和中等至优秀。然而，AMT（ICC，0.44-0.73）和 SSD（ICC，0.12-0.69）测量的测量者间可靠性较差至中等。在几乎所有测试条件下，在评估者之间和评估者内部观察到 AMT 和 SSD 测量值在统计上具有显着的等效性。结论：可以使用无创图像分析软件量化前内侧旋转膝关节松弛，在未受伤个体的中性胫骨旋转期间观察到最高 AMT。测量的可靠性和等效性在评估者内部为良好到优秀，在评估者之间为中等。